Removable fuse holder for an instrument transformer



R. S. CANNEY Dec. 24, 1968 REMOVABLE FUSE HOLDER FOR AN INSTRUMENT TRANSFORMER Filed March 22, 1967 .& E I

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Unted States Patent 3,418,615 REMOVABLE FUSE HOLDER FOR AN INSTRUMENT TRANSFORMER Robert S. Canney, Berwick, Maine, assignor to General Electric Company, a corporation of New York Filed Mar. 22, 1967, Ser. No. 625,203 5 Claims. (Cl. 337-190) ABSTRACT OF THE DISCLOSURE A removable fuse holder for converting unfused instrument transformers to fused instrument transformers. The fuse holder includes a container which is a rectangular member divided into two sections, each section being provided with the fuse clips to make electrical contact with the ends of a cartridge type fuse. One fuse clip in each section is provided with a bar member which may be inserted and electrically and mechanically secured to a primary terminal of an instrument transformer. The other fuse clip in each section is provided with a terminal member which becomes the primary terminal of the transformer when the fuse holder is in place. A cover is provided for the fuse holder, the cover carrying a pair of fuses which makes electrical contact with the fuse clips when the cover is in place. Sealing means are provided for receiving utility sealing devices to seal the cover to the container of fuse holder.

Background of invention This invention relates to instrument transformers and more particularly to a removable fuse holder for instrument transformers.

As is well known to those skilled in the instrument transformer art, and particularly potential transformers, it is often considered necessary to provide primary fuses to such transformers. These fuses are required to protect the transformer and the system to which the transformer is connected when a short circuit develops in the secondary of the transformer. The usual practice is to provide separate primary fuses in the primary line before connecting them to the transformer. Therefore, many instrument transformers are made without provisions for primary fuses. However, in other primary circuits, where it is either undesirable or impractical to provide separate primary fuses, it is, of course, necessary to use transformers which have provisions for accommodating primary fuses. Also, as is well understood, in some instrument transformers, only a single fuse is used since only one primary terminal is provided, with the second terminal being a neutral terminal. As will be apparent, transformers having provisions for fuses are of somewhat different design than unfused transformers.

The various design for both fused and unfused transformers require the utilities to stock both types of transformers, thus increasing their inventory. These various designs also require the manufacturer to manufacture the separate designs, which increase the cost of each type of transformer due to the smaller quantity of each transformer produced. From the above, it will be apparent, that there is presently a need in the instrument transformer field for a fuse holder which may be attached or removed from an instrument transformer as required by the various types of primary circuits with which the transformer is to be used.

It is therefore one object of this invention to provide a removable fuse holder for use with instrument transformers.

A further object of this invention is to provide a removable fuse holder which may be secured to the primary 3 ,418,6 15 Patented Dec. 24, 1 968 terminals of an instrument transformer, such fuse holder having another set of primary terminals.

A still further object of this invention is to provide a fuse holder for instrument transformers having a container member with fuse clips and a cover member carrying fuses to connect with such fuse clips.

Summary of invention In carrying out this invention in one form, a removable fuse holder is provided which comprises a fuse container which may be secured to the primary terminal or terminals of an instrument transformer. The fuse container is provided with at least one pair of fuse clips, one clip having means to secure the container to one primary terminal of an instrument transformer. The other fuse clip is provided with a terminal means which becomes the primary terminal of the transformer. A cover member is provided fitting over the fuse container and carrying a fuse for each pair of fuse clips. If desired, mating portions may be provided to allow a utility seal to be secured to the fuse container and cover, thereby sealing the fuse holder.

The invention which is sought to be protected will be particularly pointed out and distinctly claimed in the claims appended hereto, however it is believed that this invention and the manner in which its various objects and advantages are obtained as well as other objects and advantages thereof will be better understood from the following detailed description of 'a preferred embodiment thereof, particularly when considered in connection with the accompanying drawing.

Brief description of drawing The single figure of the drawing is an exploded perspective view of a preferred embodiment of a fuse holder according to this invention showing the manner of attachment of such fuse holder to an instrument transformer.

Description of preferred embodiment The single figure of the drawing shows the present preferred embodiment of the fuse holder of this invention. It is shown as being secured to both primary terminals of an instrument transformer and having a pair of fuses, one for each primary terminal. Of course, it will be obvious that for these instrument transformers having only a single primary terminal and a neutral terminal, it would only be necessary to provide a single fuse and the fuse holder would, therefore, be one which would contain the single fuse. It will also be apparent to those skilled in this art that various constructional details could be changed without departing from the spirit and scope of this invention.

In the drawing, a portion of an instrument transformer 10 is shown having a pair of primary terminals 12 and 14. In the usual manner, these terminals 12 and 14 are provided with openings 16 and 18, respectively, for receiving primary leads (not shown) and screws 20, 22 are provided fitting in the threaded holes 24, 26, respectively, to secure such primary leads (not shown) to the primary terminals 12 and 14.

In accordance with this preferred embodiment of the invention a fuse holder 28 is provided which comprises a container 30, generally of rectangular shape, and a cover member 70, which fits on the fuse container. As is shown, the fuse container is divided into two compartments or sections 32, 34 by a divider 36. The fuse container 30 is preferably made of an insulating material such as glass-filled thermoplastic polycarbonate resinous material which may be readily molded to the desired shape. Each compartment or section 32, 34 is provided with a pair of fuse clips 38, 40 and 42, 44, respectively, which may be molded in place, or secured by screws or other desired means, to the fuse container 30. One fuse clip in each compartment is provided with a bar or conductor member, bar 46 on fuse clip 38 and bar 48 on fuse clip 42. As is indicated in the drawing, these bars or conductors will be inserted into the opening 18, 16 respectively of the primary terminals 14, 12 of the instrument transformer 10. The other fuse clip in each compartment is provided with a primary terminal, terminal 50 on fuse clip 40 and terminal 52 on fuse clip 44. Each of these terminals 50, 52 is provided with an opening to receive a primary conductor and has a threaded member 54, 56, respectively, to secure such primary conductor to the primary terminal.

In the preferred form shown, it will be noted that the fuse container 30 is provided with four arched openings, 58, 60, 62 and 64, two in each compartment or section. Openings 60 and 62 allow the fuse container 30 to be placed over the primary terminals 18, 16 respectively and the threaded members 22 to be contained within the fuse container 30. In a similar manner, openings 58 and 64 allow the primary conductors to be inserted into the primary terminals 50, 52 and secured by threaded member 54, 56 within the container 30. As will be understood, this will serve to cover the live portions of the primary circuit, preventing accidental contact therewith and also, making it more diflicult for unauthorized persons to tamper with these connections. The divider 36 is provided with a raised portion 66 which has an opening 68 cooperating with the cover 70 to secure cover 70 to the container and seal it thereto with a utility seal.

A cover member 70 is provided which fits on the fuse container 30. The cover member 70 is also made from insulating material, preferably the same material as container 30. It is also preferred that the cover 70 be transparent. In the preferred form shown, the cover member 70 is provided with a pair of downward depending tabs 72, 74 which will fit on opposite sides of the divider 36. The cover 70 is also provided with a pair of downward depending fuse brackets 76, 78 which will receive a pair of cartridge fuses shown at 80, 82. Tabs 72, 74 and brackets 76, 78 are molded as part of cover 70. A fuse retainer 84, only one of which is shown, may be provided which will fit about the fuse body near the end cap of the cartridge fuse. The retainer 84 will fit on the fuse body between an end cap and the fuse bracket to prevent shifting of the fuse. This will ensure that the end caps of the fuses are aligned with the fuse clips in the fuse container 30 when the cover member 70 is placed on container 30.

A slot 86 is provided in fuse cover 70 into which the raised member 66 on fuse container 30 is inserted. A sealing slot 88 is provided at right angles to slot 86 and will cooperate with slot 68 when the cover 70 is in place on fuse container 30. As will be understood, the usual utility sealing wire may be inserted through mating slots 68, 88 to seal the cover 70 to fuse holder 30. A handle member 90 is also provided on the cover 70 to make it easier to insert and remove cover 70 from the container 30.

As will be apparent from the above descritpion, this invention provides a removable fuse holder which may be mounted on the primary terminals of an instrument transformer to convert an unfused instrument transformer to a fused instrument transformer. In the preferred embodiment disclosed, the fuses are mounted on the cover the fuses. Thus, the primary connections which are made inside of the fuse container cannot be made or disconnected without removing the fuses. While there has been shown and described the present preferred embodiment, it will be obvious to those skilled in this art that various and thus, the holder cannot be opened Without removing changes may be made without departing from the spirit and scope of the invention, especially as it is defined in the appended claims.

What is claimed as new and is desired to be secured by Letters Patent of the United States is:

1. A removable fuse holder for an instrument transformer comprising:

(a) at least one terminal for said transformer,

(b) a fuse container having at least one compartment,

(c) said container having at least one opening,

(d) said terminal extending through said opening,

(e) a pair of fuse clips secured in said compartment,

(1) one of said pair of fuse clips having a bar connected thereto, said bar being removably secured to said terminal of said instrument transformer,

(2) the other of said pair of fuse clips having a terminal member connected thereto, said terminal member adapted to make connection with a conductor,

(f) a cover member fitting on said fuse holder,

(1) said cover member having at least one fuse bracket adapted to contain a fuse for engaging said fuse clips.

2. A removable fuse holder as claimed in claim 1 in which a fuse retainer is provided to secure a fuse in said fuse bracket.

3. A removable fuse holder as claimed in claim 1 in which cooperating means are provided on said fuse container and said cover to receive a utility sealing means.

4. A removable fuse holder for an instrument transformer comprising:

(a) a pair of primary terminals for said transformer,

(b) a fuse container having two separate compartments,

(c) a pair of fuse clips mounted in each of said compartments,

(1) one fuse clip of each pair having a conductor member secured thereto and connected to said primary terminal of said instrument transformer,

(2) the other fuse clip in each pair having a terminal member secured thereto and connected with a primary conductor,

(d) openings provided in said container at each fuse clip to receive primary terminals and primary conductors such that said connections are made within said container,

(e) and a cover member fitting on said container,

(1) said cover member having a pair of fuse brackets, each bracket adapted to contain a fuse to engage the fuse clips in one of said compartments.

5. A removable fuse holder as claimed in claim 4 in which fuse retainer means are provided, said retainer means cooperating with said fuse brackets to secure a fuse in said fuse bracket.

References Cited UNITED STATES PATENTS 596,209 12/1897 Hunt 200-133 1,455,566 5/1923 Briggs 200 -133 XR 2,186,813 l/1940 Adam et a1. 200l33 XR 2,910,625 10/1959 Carpenter 317-15 XR 3,052,820 9/1962 Kreekon et al. 31799 BERNARD A. GILHEANY, Primary Examiner.

H. B. GILSON, Assistant Examiner.

US. Cl. X.R. 

